In-vehicle heat pump apparatuses provided with a heat pump and configured to exchange heat between refrigerant and coolant have been known. Non-Patent Literature (hereinafter, referred to as “NPL”) 1 discloses a temperature adjustment system for a vehicle provided with an in-vehicle heat pump air conditioner (HPAC) and configured to perform cooling and heating of the vehicle interior using a coolant extracted by the in-vehicle heat pump apparatus. This in-vehicle heat pump apparatus includes: a compressor that compresses refrigerant; a condenser that performs heat radiation from the refrigerant to the coolant; a cooler that cools the coolant using the refrigerant; a condenser pump that sends out the coolant to the condenser; and a cooler pump that sends out the coolant to the cooler.
Moreover, as a related art of the invention of the subject application, Patent Literature (hereinafter, referred to as “PTL”) 1 discloses a refrigerating device in which a tube of a refrigerant water heat exchanger is placed around a compressor with a space between the tube and compressor (see, FIGS. 22 and 24 of PTL 1).